DON’T KNOCK IT TIL’ YOU TIE IT: City hardware stores are seeing a rush of women coming in to buy up soft rope — the kind used for S&M play in the hit “Fifty Shades of Grey” book series. A big seller is 12-gauge, non-braided nylon, like this one bought at Lexington Hardware. Photo: NY Post: Tamara Beckwith

There’s a run on rope — and not the camping kind.

White-hot read “Fifty Shades of Grey” has left unassuming New York women so feverish, they’re snapping up all the tools and toys that bondage and S&M hunk Christian Grey introduces to “unexplored” young heroine Anastasia in the book.

They’re even slipping into hardware stores and demurely asking for bondage material — the very type of natural-filament rope in the trilogy.

“Oh, we’ve been selling rope to women,” says Clifton Kahn, owner of Lexington Hardware on the Upper East Side. “I’d say tenfold more rope than usual in the last six months. The women are definitely buying, and it’s still continuing.”

The store’s most popular item is the soft-cotton “clothes line” rope, which retails at a bargain $5 for 50 feet.

Tarzian Hardware in Park Slope, Brooklyn, has also seen a rash of rope sales. “It’s usually men buying rope, but the women, they’ve been coming in the last few months,” cashier Christina Davila told The Post. “I’ve actually read the book. So when the women buy rope, it was kind of like, ‘Hmmm, that does seem a little unusual.’ ”

Nathaniel Garber Schoen, co-owner of Garber Hardware in the West Village, says customers eager to get tied up rather than secure lumber have a telltale sign: They request softer nylon material. In which case Schoen recommends the 12-gauge, non-braided nylon — “Anything skinnier is too small. You might hurt yourself,” he says of the rope, $18 for a 50-foot spool. “For those purposes, 12-gauge is a reasonable choice and the most popular.”

But the ladies’ shopping lists don’t end with rope — there are also riding crops and handcuffs and, of course, the book’s signature silver-grey tie.

At Babeland, sales of kinky products are up nearly 30 percent in the last few months — and visits to the bondage section of their Web site have spiked 81 percent. Riding crops and handcuffs — both used in the book — are hot items. And there’s a “Fifty Shades of Grey” book and bondage kit sold online for $29 and a more extensive “Fifty Shades of Grey: Indulge Your Fantasies” kit, which includes restraints, a riding crop and “Spank Me Baby” body powder for $169.

“It’s like a juggernaut,” says Babeland co-founder Claire Cavanah. “You’d be surprised to see how very ordinary these people are who are coming in. The book is just an explosion of permission for them to try something new in the bedroom.”

Even at staid Brooks Brothers, a publicist promoted “Eight Shades of Grey Ties” among their offerings. “We may not have Fifty Shades of Grey Ties, but we do have Eight Shades of Grey Ties,” he wrote The Post, forwarding a link to a collection of neckwear that retails from $44.50 to $175. Overall, men’s necktie sales are up 23 percent in the last year, according to NPD Group, a market research firm.

The shopping spree for sex treats doesn’t stop there. Babeland stores are offering “Fifty Shades” classes inspired by the scintillating series. The first workshop in SoHo a few weeks ago — flowing with cocktails, gift bags and bondage advice — reached maximum capacity of 150 people, with 100 hot-and-bothereds turned away. Organizers expect this Sunday’s “Fifty Shades of Spanking” class — with the course description: “Learn how to give and get a good smack while you discover new ways of teasing, touching and stimulating your partner” — on the Lower East Side similarly swell with libidinous ladies.

Three hundred people had signed up for next Friday’s Brooklyn class; that’s three times event capacity, but Babeland says it will try to repeat the workshop and rotate people in throughout the night.

“There are so many women showing up to these events, the stigma is disappearing,” says Cavanah, who likens the experience to attending an innocuous L.L.Bean lecture on fly fishing.

“It’s safety in numbers.”

One 29-year-old administrative assistant from Midtown even brought her 56-year-old mom and 26-year-old sister (all “Fifty” readers) to the SoHo workshop.

“My mom planned a visit over the time of the event, and my sister and I didn’t want to miss it,” says Rebecca, who asked that her last name not be used. “So we called her up and said, ‘Guess what? We’re bringing you to a party on Friday!’ It was a little weird at first, but we had a blast together.”

Rebecca describes herself as “mild-mannered” about sex “B.F.” (“Before ‘Fifty’ ”). Until last month, she’d never set foot in a sex shop and certainly never imagined she’d be attending a bondage how-to.

“The book broke down a wall,” she explains. “I mean, it’s so terribly written — it makes ‘Twilight’ read like Shakespeare — but you can’t put it down. You can’t stop thinking about it.”

The series has created a sisterhood in cubicles and on the subways of New York.

“For every girl in my office, it’s become this weird secret code: ‘Are you reading it? Are you still in it?’ ” laughs Rebecca.

Rachel, who requested that her last name not be used, cracked the series in April and said her boyfriend certainly isn’t complaining. “I feel bad if you read the book and you don’t have a person or a toy to help you out!” she laughs.

Lidia Bonilla, a Brooklyn-based banking compliance consultant who also attended the workshop, is so fascinated by the “Fifty” phenomenon that she’s now launching her own company — a sex-toy accessories line.

“It’s changed my perspective,” raves the 33-year-old.

“Bondage has never been my thing until I read about it.”

In fact, it seems the entire city is feeling a bit like Anastasia this summer: “A quivering mass of raging female hormones . . . contort[ing] with potent, liquid, needy desire.”